KR102161812B1 - System and Method for Controlling MPPT of Photovoltaic System Using Active Power Control - Google Patents

Abstract

The present invention relates to a device and a method for controlling MPPT of a photovoltaic system using active power control, which enable high power generation efficiency of the photovoltaic system by performing MPPT based on active power control when the amount of insolation fluctuates to quickly and accurately follow the maximum output point. The device for controlling MPPT of the photovoltaic system using active power control includes: a solar panel; a solar inverter unit for converting and outputting DC power input from the solar panel into AC power used as commercial power; and an active power-base inverter control unit which determines a reference value (P_mpp) for the solar inverter output (P_inv) by using the curve (P_mpp) connecting the maximum output points according to the change in solar radiation in the P-V curve of the relationship between the solar output and the terminal voltage, measures a terminal voltage (V_pv) of the solar panel, and performs the operation by the maximum power point tracking (MPPT) control which tracks the value of a terminal voltage which varies depending on the amount of insolation in the solar inverter unit.

Description

System and Method for Controlling MKP of Photovoltaic System Using Active Power Control}

The present invention relates to a photovoltaic power generation system, and in particular, by performing MPPT based on active power control, the maximum power point is quickly and accurately followed, and the active power control is used to realize high power generation efficiency of the photovoltaic power generation system. It relates to an apparatus and method for controlling MPPT of a solar power system.

The output-terminal voltage relationship of a solar power generation system that generates power by receiving solar energy has a convex upward characteristic.

There is a value of the terminal voltage to produce the maximum output of the solar power generation system, and it has a characteristic that the terminal voltage to obtain the maximum output varies as the amount of solar radiation changes.

Therefore, in order for the solar power generation system to produce the maximum power as the amount of insolation changes, it is essential to control the maximum power point tracking (MPPT) that tracks the value of the terminal voltage that varies according to the amount of insolation.

The MPPT control method of the solar power generation system mainly used in the prior art includes a Perturbation & Observation (P&O) method.

1 is a configuration diagram of a general photovoltaic power generation system, and FIG. 2 is a configuration diagram of a conventional voltage control-based photovoltaic inverter controller.

The photovoltaic power generation system is located between the photovoltaic panel 10 that generates electric energy through the photoelectric effect of the incidence of sunlight, and the photovoltaic panel 10 and the photovoltaic inverter 12 to reduce the terminal voltage in a narrow range. A parallel capacitor 11 for maintaining, and a solar inverter 12 that converts and outputs AC power so that the DC power input from the solar panel 10 can be used as commercial power, and the solar inverter 12 It includes a filter 13 for removing noise included in the output AC electrical energy, and a utility grid 14 connected to the output terminal of the filter 13.

In the prior art, a solar power generation system is controlled through a voltage control-based MPPT control method, and MPPT is performed through a command value of the terminal voltage by measuring a terminal voltage and an output current of a solar panel.

) 및 병렬커패시터(11)의 단자전압(V_pv)을 입력받아 태양광 인버터(12) 제어를 위한 인버터 전력 제어 신호(

)를 출력하는 DC-전압 제어기(DC-Voltage Controller)(22)와, DC-전압 제어기(22)로부터 인버터 출력 제어 신호(

)를 입력받아 회전 좌표계의 전류 신호(

,

)를 출력하는 전력 제어기(Power Controller)(23)와, 계통 전압(v_grid)을 입력받아 계통 전압의 동기화를 위한 위상각(θ)을 출력하는 PLL(Phase Locked Loop)(25)과, 계통 전류(i_grid) 및 PLL(Phase Locked Loop)(25)의 위상각(θ), 회전 좌표계의 전류 신호(

,

)를 입력으로 PWM 제어를 위한 신호(m)를 출력하는 전류 제어기(Current Controller) (24)와, 전류 제어기(24)의 신호(m)를 입력으로 태양광 인버터(12)의 출력을 제어하기 위한 PWM 제어 신호를 출력하는 PWM 제어 신호 생성기(26)를 포함한다.For voltage control-based MPPT control, as shown in FIG. 2, a value of a terminal voltage that varies depending on the amount of insolation by receiving a current value (i _pv ) of the solar panel 10 and a terminal voltage (V _pv ) of the parallel capacitor 11 The MPPT control unit 21 that controls the maximum power point tracking (MPPT) to track the MPPT and the output of the MPPT control unit 21 (

) And a terminal voltage (V _pv ) of the parallel capacitor 11 and an inverter power control signal for controlling the solar inverter 12 (

) Outputting a DC-Voltage Controller 22 and an inverter output control signal from the DC-voltage controller 22 (

) And the current signal of the rotation coordinate system (

,

), a PLL (Phase Locked Loop) 25 that receives the _grid voltage (v _grid ) and outputs a phase angle (θ) for synchronization of the grid voltage, and the grid Current (i _grid ) and phase angle (θ) of PLL (Phase Locked Loop) (25), current signal (

,

) As an input to control the output of a current controller (24) that outputs a signal (m) for PWM control and a signal (m) of the current controller (24) as an input. It includes a PWM control signal generator 26 for outputting a PWM control signal for.

This method is a method of finding the maximum output point by changing the terminal voltage of the solar power generation system slightly, then comparing the changed solar power output with the previous output value, and changing the terminal voltage in the direction of increasing the output.

However, if the amount of change of the terminal voltage to be changed is small, the vibration near the maximum output point is small, but the MPPT tracking speed is slow. If the change amount is large, the MPPT following speed is fast, but there is a problem that vibration occurs near the maximum output point.

A method of using ESS is being considered to self-mitigating the output vibration of such a solar power generation system, but this has a problem of increasing the installation cost of the solar power generation system.

In addition, when the P&O method is used, the solar power output changes rapidly when the amount of insolation increases or decreases.This sudden fluctuation in the solar power output leads to a rapid fluctuation in the frequency of the power grid. It is required to have a negative impact, such as an increase in power grid operating costs.

If the above problems are not solved, when a large-capacity photovoltaic power generation system is connected to the power grid, the output limit of the photovoltaic power generation system becomes inevitable, resulting in a deterioration in the economics of the photovoltaic power generation system.

In addition, this method has a disadvantage in that a separate current sensor is required to calculate the output of the photovoltaic power generation system, thereby increasing the cost.

As described above, the control of the solar power generation system using the MPPT method based on the voltage control of the prior art has a problem in that the tracking speed is slow and vibrating severely near the maximum output point, and thus it cannot converge to the maximum output point.

In addition, there is a problem due to a sudden change in output due to a feed-forward control for maintaining a voltage when the amount of insolation changes, and there is a problem of an increase in cost by using a current sensor for calculating the solar panel output.

In order to minimize the influence of the high power generation efficiency of the solar power generation system and the frequency fluctuation of the power grid, it must be able to quickly and accurately follow the maximum output point.

In addition, in order to lower the initial investment cost of the solar power generation system, the power generation system price must be low.

Therefore, even if the amount of insolation changes, the output gradually increases and reaches the target value very quickly without overshoot, and development of a new technology is required to provide a solar power generation system without vibration even in the vicinity of the maximum output point. .

Korean Patent Registration No. 10-1595060 Republic of Korea Patent Publication No. 10-2017-0064874 Republic of Korea Patent Publication No. 10-2013-0032035

The present invention is to solve the problem of the solar power generation system control technology of the prior art, and by performing MPPT based on active power control, it is possible to implement high power generation efficiency of the solar power generation system by quickly and accurately following the maximum output point. An object of the present invention is to provide an apparatus and method for controlling MPPT of a solar power generation system using active power control.

The present invention is for MPPT control of a photovoltaic power generation system using active power control in which the output gradually increases even if the amount of insolation changes and reaches the target value very quickly without overshoot, and there is no vibration even in the vicinity of the maximum output point. It is an object to provide an apparatus and method.

The present invention measures only the terminal voltage of the solar panel, determines a reference value for the solar inverter output from this value, and performs MPPT to quickly and accurately follow the maximum output point, resulting in high power generation efficiency and power grid frequency fluctuations. An object of the present invention is to provide an apparatus and method for MPPT control of a photovoltaic power generation system using active power control to minimize the impact of

Other objects of the present invention are not limited to the objects mentioned above, and other objects that are not mentioned will be clearly understood by those skilled in the art from the following description.

An apparatus for controlling MPPT of a solar power generation system using active power control according to the present invention for achieving the above object is a solar panel; AC power to use DC power input from the solar panel as commercial power Solar inverter unit that converts and outputs; The relationship between the solar output and the terminal voltage The reference value for the solar inverter output (P _inv ) by using the curve ( P _mpp ) connecting the maximum output points according to the change in solar radiation in the PV curve (P _mpp ), measure the terminal voltage (V _pv ) of the solar panel, and track the value of the terminal voltage that varies depending on the amount of insolation in the solar inverter. It characterized in that it comprises a; active power-based inverter control unit to perform the operation by.

Here, the solar inverter unit includes a parallel capacitor positioned between the solar panel and the solar inverter to maintain the terminal voltage within a certain range, and the DC power received from the solar panel as AC power to be used as commercial power. It characterized in that it comprises a solar inverter that converts and outputs, a filter that removes noise included in the AC electrical energy output from the solar inverter, and a utility grid connected to the filter output terminal.

)를 출력하는 인버터 전력 제어신호 출력부와,인버터 전력 제어신호 출력부로부터 인버터 전력 제어신호(

)를 입력받아 회전 좌표계의 전류 신호(

,

)를 출력하는 전력 제어기(Power Controller)와,계통 전압(v_grid)을 입력받아 계통 전압의 동기화를 위한 위상각(θ)을 출력하는 PLL(Phase Locked Loop)과,계통 전류(i_grid) 및 PLL(Phase Locked Loop)의 위상각(θ), 회전 좌표계의 전류 신호(

,

)를 입력으로 PWM 제어를 위한 출력 제어 신호(m)를 출력하는 전류 제어기(Current Controller)와,전류 제어기의 출력 제어 신호(m)를 입력으로 태양광 인버터의 출력을 제어하기 위한 PWM 제어 신호를 출력하는 PWM 제어 신호 생성기를 포함하는 것을 특징으로 한다.In addition, the active power-based inverter control unit receives the terminal voltage (V _pv ) of the parallel capacitor and determines a reference value (P _mpp ) for the solar inverter output (P _inv ) from this value, and the inverter power control signal (

), and an inverter power control signal from the inverter power control signal output unit (

) And the current signal of the rotation coordinate system (

,

), a PLL (Phase Locked Loop) that receives a system voltage (v _grid ) and outputs a phase angle (θ) for synchronizing the system voltage, and a system current (i _grid ) PLL (Phase Locked Loop) phase angle (θ), rotational coordinate system current signal (

,

) As an input, and a current controller that outputs an output control signal (m) for PWM control, and a PWM control signal to control the output of a solar inverter by inputting the output control signal (m) of the current controller. It characterized in that it comprises a PWM control signal generator to output.

)를 출력하는 단계; 전력 제어기(Power Controller)가 인버터 전력 제어신호 출력부로부터 인버터 전력 제어신호(

)를 입력받아 회전 좌표계의 전류 신호(

,

)를 출력하는 단계;전류 제어기(Current Controller)가 계통 전류(i_grid) 및 PLL(Phase Locked Loop)의 위상각(θ), 회전 좌표계의 전류 신호(

,

)를 입력으로 PWM 제어를 위한 출력 제어 신호(m)를 출력하는 단계;PWM 제어 신호 생성기에서 전류 제어기의 출력 제어 신호(m)를 입력으로 태양광 인버터의 출력을 제어하기 위한 PWM 제어 신호를 출력하는 단계;태양광 인버터에서 일사량에 따라 달라지는 단자전압의 값을 추종하는 최대 전력점 추종(Maximum Power Point Tracking, MPPT) 제어에 의한 동작을 수행하는 단계;를 포함하는 것을 특징으로 한다.A method for controlling MPPT of a photovoltaic power generation system using active power control according to the present invention for achieving another object comprises: inputting a terminal voltage (V _pv ) of a parallel capacitor to an active power-based inverter control unit; active power-based inverter The inverter power control signal output unit of the control unit receives the terminal voltage (V _pv ) and determines a reference value (P _mpp ) for the solar inverter output (P _inv ) from this value.

) Outputting; Inverter power control signal (power controller) from the inverter power control signal output

) And the current signal of the rotation coordinate system (

,

); The current controller outputs the system current (i _grid ) and the phase angle (θ) of the PLL (Phase Locked Loop), and the current signal (

,

) Outputting an output control signal (m) for PWM control as an input; outputting a PWM control signal for controlling the output of the solar inverter by inputting the output control signal (m) of the current controller from the PWM control signal generator And performing an operation according to a maximum power point tracking (MPPT) control that tracks a value of a terminal voltage that varies according to the amount of insolation in the solar inverter.

)를 출력하는 단계에서, 태양광 출력과 단자전압 사이의 관계 P-V 곡선에서 일사량 변화에 따른 최대 출력점들을 연결한 곡선(P _mpp )을 이용하여 태양광 인버터 출력(P_inv)을 위한 기준값(P_mpp)을 정하는 것을 특징으로 한다.Here, by setting the reference value (P _mpp ) for the solar inverter output (P _inv ), the inverter power control signal (

), the reference value (P _inv ) for the solar inverter output (P _inv ) using the curve ( P _mpp ) connecting the maximum output points according to the change in solar radiation in the relationship between the solar power output and the terminal voltage in the PV curve. _mpp ).

And the power supplied to the parallel capacitor ( P _Cpv ) is the difference between the solar panel output ( P _pv ) and the solar inverter output ( P _inv ),

으로 정의되고, 여기서, C _pv 는 병렬 커패시터의 커패시턴스이며, V _pv 는 태양광 패널의 단자전압, P _pv 는 일사량, 온도, V _pv 에 의해서 결정되며, P _inv 는 태양광 인버터의 유효 전력 제어를 통해 조절되는 것을 특징으로 한다.

Where C _pv is the capacitance of the parallel capacitor, V _pv is the terminal voltage of the solar panel, P _pv is determined by the amount of insolation, temperature, and V _pv , and P _inv is the active power control of the solar inverter. It characterized in that it is controlled through.

And when the amount of insolation changes from the first value to a second value that is greater than the first value, the output of the solar panel ( P _pv ) is from the solar output (A) for the first value of insolation to the second value of insolation. It moves to the output (A'), and the solar inverter output (P _inv ) does not move, so the output ( P _pv ) of the solar panel has a larger value than the solar inverter output (P _inv ).

And the fact that the output of the solar panel ( P _pv ) is larger than the output of the solar inverter (P _inv ) means that the right side of the equation has a positive value.If the solar radiation amount increases, the terminal voltage of the solar panel ( V _pv ) is characterized by increasing.

And when the terminal voltage ( V _pv ) of the solar panel increases, the output ( P _pv ) of the solar panel is the relationship between the solar output and the terminal _voltage.The position of the output point in the PV curve is different from (A') ( B'), and the solar inverter output (P _inv ) moves from (A) to another position (B) in the curve ( P _mpp ) that connects the maximum output points according to the change in insolation. In this case, since the output ( P _pv ) of the solar panel still has a larger value than the output of the solar inverter (P _inv ), the terminal voltage ( V _pv ) of the solar panel is further increased.

And when the terminal voltage ( V _pv ) of the solar panel further increases, the output of the solar panel ( P _pv ) follows the relationship PV curve between the solar output and the terminal voltage, and the solar inverter output (P _inv ) becomes The position of the output point is moved to the point where the two curves intersect along the curve ( P _mpp ) that connects the maximum output points according to the change in insolation, so that the output of the solar panel ( P _pv ) becomes the solar inverter output (P _inv ). Since they have the same value, the terminal voltage ( V _pv ) of the solar panel converges, and the solar inverter output (P _inv ) is characterized by having a constant value.

The apparatus and method for controlling MPPT of a solar power generation system using active power control according to the present invention as described above have the following effects.

First, MPPT is performed based on active power control to quickly and accurately follow the maximum output point to realize high power generation efficiency of the solar power generation system.

Second, even if the amount of insolation changes, the output gradually increases to reach the target value very quickly without overshoot, and there is no vibration even in the vicinity of the maximum output point.

Third, by measuring only the terminal voltage of the solar panel, and by determining the reference value for the solar inverter output from this value, MPPT is performed to quickly and accurately follow the maximum output point to realize high power generation efficiency of the solar power generation system and to change the frequency of the power grid. Can be minimized.

Fourth, it is possible to quickly follow the maximum power point for frequent insolation changes, and to have a constant output even after the follow-up, so that more generation can be expected for the same insolation and temperature conditions, which helps to secure the economic feasibility of the solar power generation system.

Fifth, since it is possible to minimize the frequency fluctuation of the system by gently controlling the change in the power supplied to the system even with a sudden change in insolation, it is helpful in improving the acceptance of the solar power generation system.

Sixth, by reducing the number of current sensors used to control the solar power generation system, it is possible to lower the manufacturing cost and lower the initial investment cost of solar power generation.

1 is a configuration diagram of a general solar power generation system
Figure 2 is a configuration diagram of a conventional voltage control-based solar inverter controller
3 is a block diagram of an apparatus for controlling MPPT of a solar power generation system using active power control according to the present invention
4 is a flow chart showing a method for controlling MPPT of a solar power generation system using active power control according to the present invention
5 is a graph showing a solar panel PV curve
6 is a graph showing a solar panel P _mpp curve
7 is a graph showing a process of tracking the maximum power point when the amount of insolation changes according to the present invention
8 is a graph comparing the P&O method and the solar inverter output power according to the present invention when the amount of insolation changes

Hereinafter, a preferred embodiment of an apparatus and method for controlling MPPT of a photovoltaic power generation system using active power control according to the present invention will be described in detail.

Features and advantages of an apparatus and method for controlling MPPT of a solar power generation system using active power control according to the present invention will become apparent through detailed description of each embodiment below.

3 is a block diagram of an apparatus for controlling MPPT of a solar power generation system using active power control according to the present invention.

The apparatus and method for MPPT control of a solar power generation system using active power control according to the present invention measures only the terminal voltage of the solar panel, and determines a reference value for the solar inverter output from this value, and performs MPPT to perform the maximum output. By following the point quickly and accurately, it is possible to minimize the effect of high power generation efficiency and power grid frequency fluctuations of the solar power generation system.

To this end, the apparatus for MPPT control of a solar power generation system using active power control according to the present invention is largely as shown in FIG. 3, and converts the solar panel 100 and DC power input from the solar panel into commercial power. Active power that performs MPPT by measuring only the terminal voltage of the solar inverter unit 200 and the solar panel 100 that converts and outputs AC power so that it can be used, and determines a reference value for the solar inverter output from this value. It includes a base inverter control unit 300.

Specifically, it includes a solar panel 100 that generates electric energy through a photoelectric effect according to the incidence of sunlight.

The photovoltaic inverter unit 200 is located between the photovoltaic panel 100 and the photovoltaic inverter 36 to maintain the terminal voltage in a narrow range, and a parallel capacitor 31 received from the photovoltaic panel 100 A solar inverter 36 that converts DC power into AC power and outputs it so that it can be used as commercial power, and a filter 37 and a filter that removes noise contained in the AC electrical energy output from the solar inverter 36 (37) It includes a utility grid (38) connected to the output terminal.

)를 출력하는 인버터 전력 제어신호 출력부(32)와, 인버터 전력 제어신호 출력부(32)로부터 인버터 전력 제어신호(

)를 입력받아 회전 좌표계의 전류 신호(

,

)를 출력하는 전력 제어기(Power Controller)(33)와, 계통 전압(v_grid)을 입력받아 계통 전압의 동기화를 위한 위상각(θ)을 출력하는 PLL(Phase Locked Loop)(35)과, 계통 전류(i_grid) 및 PLL(Phase Locked Loop)(35)의 위상각(θ), 회전 좌표계의 전류 신호(

,

)를 입력으로 PWM 제어를 위한 출력 제어 신호(m)를 출력하는 전류 제어기(Current Controller)(34)와, 전류 제어기(34)의 출력 제어 신호(m)를 입력으로 태양광 인버터(36)의 출력을 제어하기 위한 PWM 제어 신호를 출력하는 PWM 제어 신호 생성기(39)를 포함한다.The active power-based inverter control unit 300 receives the terminal voltage (V _pv ) of the parallel capacitor 31 and determines a reference value (P _mpp ) for the solar inverter output (P _inv ) from this value, and the inverter power control signal (

) From the inverter power control signal output unit 32 and the inverter power control signal output unit 32 to output the inverter power control signal (

) And the current signal of the rotation coordinate system (

,

), a PLL (Phase Locked Loop) 35 that receives the _grid voltage (v _grid ) and outputs a phase angle (θ) for synchronizing the grid voltage, and the grid Current (i _grid ) and phase angle (θ) of PLL (Phase Locked Loop) (35), current signal (

,

) As an input to output an output control signal (m) for PWM control, and an output control signal (m) of the current controller 34 as inputs of the solar inverter 36 And a PWM control signal generator 39 for outputting a PWM control signal for controlling the output.

A method for controlling the MPPT of a solar power generation system using active power control according to the present invention will be described in detail as follows.

4 is a flow chart showing a method for MPPT control of a solar power generation system using active power control according to the present invention.

First, when the solar panel 100 generates electric energy through the photoelectric effect according to the incidence of sunlight, the active power-based inverter control unit 300 controls the terminal voltage (V) of the solar panel 100 through the parallel capacitor 31. _pv ) is inputted (S401)

)를 출력한다.(S402)Then, the inverter power control signal output unit 32 receives the terminal voltage (V _pv ) and determines a reference value (P _mpp ) for the solar inverter output (P _inv ) from this value, and the inverter power control signal (

) Is output (S402)

)를 입력받아 회전 좌표계의 전류 신호(

,

)를 출력한다.(S403)And the power controller (Power Controller) 33 from the inverter power control signal output unit 32, the inverter power control signal (

) And the current signal of the rotation coordinate system (

,

) Is output (S403)

,

)를 입력으로 PWM 제어를 위한 출력 제어 신호(m)를 출력한다.(S404)Then, the current controller 34 is the system current (i _grid ) and the phase angle (θ) of the PLL (Phase Locked Loop) 35, the current signal (

,

) As an input to output an output control signal (m) for PWM control (S404)

Then, the PWM control signal generator 39 outputs a PWM control signal for controlling the output of the solar inverter 36 by inputting the output control signal m of the current controller 34 (S405), and the solar inverter ( In 36), the operation by the maximum power point tracking (MPPT) control that tracks the value of the terminal voltage that varies according to the amount of insolation is performed (S406).

The MPPT control based on active power control of an apparatus and method for controlling MPPT of a solar power generation system using active power control according to the present invention having such a configuration will be described in detail as follows.

5 is a graph showing a solar panel PV curve, and FIG. 6 is a graph showing a solar panel P _mpp curve.

A parallel capacitor is essentially connected between the solar panel and the solar inverter to keep the terminal voltage within a narrow range. The power supplied to the parallel capacitor ( P _Cpv ) is the output of the solar panel ( P _pv ) and the solar inverter. It can be expressed as the difference in the output ( P _inv ), and is as follows.

Here, C _pv is the capacitance of the parallel capacitor, and V _pv is the terminal voltage of the solar panel. In addition, P _pv is determined by the amount of insolation, temperature, and V _pv , and P _inv is adjustable through the active power control of the solar inverter.

The relationship between the solar output and the terminal voltage is called a P-V curve, and FIG. 5 shows a P-V curve in the case of various amounts of insolation when the temperature is constant.

Since the P-V curve has a convex upward characteristic, the terminal voltage that produces the maximum output has one value depending on the amount of insolation.

FIG. 6 shows a curve ( P _mpp ) connecting the maximum output points of the PV curve at various amounts of insolation of FIG. 5, and P _mpp has a characteristic that varies depending on the terminal voltage.

In the present invention, MPPT based on active power control is performed, and P _mpp of FIG. 6 is used as a reference value for the solar inverter output ( P _inv ).

7 is a graph showing a process of tracking the maximum power point when the amount of insolation changes according to the present invention.

7 shows the maximum power point tracking process according to the present invention when the solar radiation amount is changed from 400 W/m ² to 1000 W/m ² .

Assuming that the solar power generation system is performing MPPT when the solar irradiation is 400 W/m ² , both P _pv and P _inv become 1250 W, and the terminal voltage at this time is 332 V, and the operating point is as shown in FIG. 7. It becomes point A.

At this time, assuming that the insolation increased from 400 W/m ² to 1000 W/m ² , P _pv moves from A to A', whereas P _inv stays at A.

Therefore, P _pv has a value greater than P _inv , which means that the right side of Equation 1 has a positive value, and Vpv is increased by Equation 1.

In this case, P _inv moves from A to B, while P _pv moves from _A'to B'. Even in this case, the right side of Equation 1 also has a positive value, so that Vpv gradually increases.

In this way, as Vpv gradually increases, P _inv goes through C and D to reach E, and P _pv also goes through _C'and D'to E'(same as E), where E (or E') P _pv and P _inv become the same. In this case, since the right side of Equation 1 becomes 0, Vpv does not increase or decrease any more, and remains at the point of E.

Specifically, when the amount of insolation changes from the first value (400 W/m ² ) to a second value greater than the first value (1000 W/m ² ), the output of the solar panel ( P _pv ) is equal to the first value of insolation. From the output of the solar panel to (point A in Fig. 7) to the output of the solar panel for the second value of insolation (point A'in Fig. 7), the solar inverter output (P _inv ) stays at point A. Therefore, the output of the solar panel ( P _pv , point A') has a larger value than the output of the solar inverter (P _inv , A).

And the fact that the output of the solar panel ( P _pv ) is larger than the output of the solar inverter (P _inv ) means that the right side of the equation has a positive value.If the solar radiation amount increases, the terminal voltage of the solar panel ( V _pv ) is increasing.

As described above, when the terminal voltage ( V _pv ) of the solar panel increases, the output ( P _pv ) of the solar panel moves from point _A'in FIG. 7 to point _B'in FIG. 7, and the solar inverter output (P _inv ) Moves from point A to B, and even in this case, the output of the solar panel ( P _pv ) has a larger value than the output of the solar inverter (P _inv ), so the terminal voltage ( V _pv ) of the solar panel is Increases further.

As such, when the terminal voltage ( V _pv ) of the solar panel further increases, the output ( P _pv ) of the solar panel moves from point _B'to point _C'and point D'in FIG. 7 to point E', When the solar inverter output (P _inv ) moves from point B to point C, and then to point E, the solar panel output ( P _pv ) has the same value as the solar inverter output (P _inv ). , The terminal voltage ( V _pv ) of the solar panel converges, and the solar inverter output (P _inv ) has a constant value.

8 is a graph illustrating a comparison between a P&O method and a solar inverter output power according to the present invention when insolation is changed.

When the amount of insolation changes to 400 W/m ² → 600 W/m ² → 1000 W/m ² → 600 W/m ² → 400 W/m ² at 0.1 second intervals, P&O method and active power control according to the present invention The output of the MPPT execution method based on is compared.

As shown in Fig. 8, in the P&O method, the output increases sharply at the moment the amount of insolation changes, overshoot occurs, and not only follows the maximum output point late, but also vibration is very severe in the vicinity of the maximum output point. Able to know.

In contrast, the MPPT execution method based on the active power control according to the present invention shows that even if the amount of insolation changes, the output gradually increases to reach the target value very quickly without overshoot, and there is no vibration even in the vicinity of the maximum output point. I can.

The apparatus and method for MPPT control of a solar power generation system using active power control according to the present invention described above, even if the amount of insolation changes, the output gradually increases to reach the target value very quickly without overshoot, and the maximum Since there is no vibration in the vicinity of the output point, it is possible to quickly follow the maximum power point for frequent insolation changes, and to have a constant output even after the follow-up, so that more generation can be expected for the same insolation and temperature conditions.

As described above, it will be understood that the present invention is implemented in a modified form without departing from the essential characteristics of the present invention.

Therefore, the specified embodiments should be considered from a descriptive point of view rather than a limiting point of view, and the scope of the present invention is shown in the claims rather than the above description, and all differences within the scope equivalent thereto are included in the present invention. It will have to be interpreted.

100. Solar Panel
200. Solar inverter unit
300. Active power-based inverter control unit

Claims (10)

Solar panels;
A solar inverter unit converting and outputting DC power input from the solar panel into AC power so that it can be used as commercial power;
Relationship between solar power output and terminal voltage The reference value (P _mpp ) for the solar inverter output (P _inv ) is determined by using the curve ( P _mpp ) connecting the maximum output points according to the change in solar radiation in the PV curve. Active power base that measures the terminal voltage (V _pv ) of the panel and performs the operation by the Maximum Power Point Tracking (MPPT) control that tracks the value of the terminal voltage that varies depending on the amount of insolation in the solar inverter. An apparatus for controlling MPPT of a solar power generation system using active power control, comprising: an inverter control unit. The method of claim 1, wherein the solar inverter unit,
A parallel capacitor located between the solar panel and the solar inverter to keep the terminal voltage within a certain range,
A solar inverter that converts and outputs DC power received from the solar panel into AC power so that it can be used as commercial power,
MPPT control of a solar power generation system using active power control, characterized in that it includes a filter that removes noise included in the AC electrical energy output from the solar inverter and a utility grid connected to the filter output terminal. Device for. The method of claim 1, wherein the active power-based inverter control unit,
_Receive the terminal voltage (V _pv ) of the parallel capacitor and set the reference value (P _mpp ) for the solar inverter output (P _inv ) from this value, and the inverter power control signal (

An inverter power control signal output unit that outputs ),
Inverter power control signal from the inverter power control signal output unit (

) And the current signal of the rotation coordinate system (

,

A power controller that outputs ), and
PLL (Phase Locked Loop) that receives the _grid voltage (v _grid ) and outputs a phase angle (θ) for synchronization of the grid voltage,
System current (i _grid ) and phase angle (θ) of PLL (Phase Locked Loop), current signal (

,

) As an input to output an output control signal (m) for PWM control, and
MPPT control of a solar power generation system using active power control, characterized in that it includes a PWM control signal generator that outputs a PWM control signal for controlling the output of the solar inverter as an input of the output control signal (m) of the current controller. Device for. Inputting a terminal voltage (V _pv ) of the parallel capacitor to an active power-based inverter controller;
The inverter power control signal output unit of the active power-based inverter control unit receives the terminal voltage (V _pv ) and determines a reference value (P _mpp ) for the solar inverter output (P _inv ) from this value.

) Outputting;
Inverter power control signal (power controller) from the inverter power control signal output

) And the current signal of the rotation coordinate system (

,

) Outputting;
The current controller is the system current (i _grid ) and the phase angle (θ) of the PLL (Phase Locked Loop), and the current signal (

,

Outputting an output control signal (m) for PWM control as an input;
Outputting a PWM control signal for controlling the output of the solar inverter by inputting the output control signal (m) of the current controller in the PWM control signal generator;
Performing an operation by controlling a maximum power point (MPPT) that tracks a value of a terminal voltage that varies according to the amount of insolation in a solar inverter; solar power using active power control, comprising: Method for MPPT control of power generation system. The inverter power control signal according to claim 4, wherein a reference value (P _mpp ) for the solar inverter output (P _inv ) is determined.

In the step of printing ),
The relationship between the solar power output and the terminal voltage Characterized in that the reference value (P _mpp ) for the solar inverter output (P _inv ) is determined using the curve ( P _mpp ) connecting the maximum output points according to the change in solar radiation in the PV curve. Method for MPPT control of solar power generation system using active power control. The method of claim 4, wherein the power supplied to the parallel capacitor ( P _Cpv ) is expressed by a difference between the output of the solar panel ( P _pv ) and the output of the solar inverter ( P _inv ),

Is defined as,
Here, C _pv is the capacitance of the parallel capacitor, V _pv is the terminal voltage of the solar panel, P _pv is determined by the amount of insolation, temperature, and V _pv , and P _inv is controlled through the active power control of the solar inverter. A method for controlling MPPT of a solar power generation system using active power control, characterized in that. The method of claim 6, wherein when the amount of insolation changes from the first value to a second value greater than the first value,
The output of the solar panel ( P _pv ) moves from the solar output (A) for the first value of insolation to the solar output (A') for the second value of insolation, and the output of the solar inverter (P _inv ) moves. The method for MPPT control of a photovoltaic power generation system using active power control, characterized in that the output of the solar panel ( P _pv ) has a larger value than that of the photovoltaic inverter output (P _inv ). The method of claim 7, wherein the solar panel output ( P _pv ) having a larger value than the solar inverter output (P _inv ) means that the right side of the equation has a positive value. Method for MPPT control of a solar power generation system using active power control, characterized in that the terminal voltage ( V _pv ) of the photovoltaic panel increases. The method of claim 8, wherein when the terminal voltage ( V _pv ) of the solar panel increases,
The output of the solar panel ( P _pv ) is the relationship between the solar output and the terminal voltage The position of the output point in the PV curve moves from (A') to another position (B'), and the solar inverter output (P _inv ) The position of the output point moves from (A) to another position (B) in the curve ( P _mpp ) that connects the maximum output points according to the change in insolation,
In this case, since the output of the solar panel ( P _pv ) still has a larger value than the output of the solar inverter (P _inv ), the terminal voltage ( V _pv ) of the solar panel is further increased. Method for MPPT control of solar power generation system using. The method of claim 9, wherein when the terminal voltage ( V _pv ) of the solar panel further increases,
The output of the solar panel ( P _pv ) follows the relationship PV curve between the solar output and the terminal voltage, and the solar inverter output (P _inv ) is the curve ( P _mpp ) that connects the maximum output points according to the change in insolation. Therefore, the position of the output point is moved to the point where the two curves intersect, and the output of the solar panel ( P _pv ) has the same value as the output of the solar inverter (P _inv ).
A method for MPPT control of a solar power generation system using active power control, characterized in that the terminal voltage ( V _pv ) of the solar panel converges and the solar inverter output (P _inv ) has a constant value.

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